Workpiece stages in various photolithography machines need to be moved out from the photolithography machines for maintenance or repair after a certain period of running or upon malfunctioning and then moved into the photolithography machines after the maintenance or repair. In order to shorten the time required for maintenance or repair and ensure the safety of the equipment when it is moved in and out, automation of the move-in and move-out process is desirable.
Most existing move-in and move-out devices are slider-crank mechanisms with hinges that are not coplanar due to space constraints. This may lead to excessive torques at the hinges, which can make the mechanisms susceptible to jamming. Moreover, most of the conventional mechanisms are usually used alone, tending to exert an excessive pressure onto the ground. For this reason, it is possible for them to lean or even tip over. In such a situation, the workpiece stage loaded on the mechanism may drop off, leading to failure of the move-in and move-out process.